The invention relates to an administering apparatus having connecting casing sections. The invention is suited to an administering apparatus having a disposable portion for one-time use and a drive device for repeated use. Such drive device may be formed as a dosing and drive device. The present invention thus may relate to, for example, a semi-disposable pens. Alternately, the invention is suited for a further type of injection apparatus, infusion apparatus, inhalation apparatus, for example wherein the product is vaporized by a vaporizing means of the inhalation apparatus, or any other suitable type of apparatus for administering a fluid product. The invention can, however, also be advantageously employed for other injection apparatus and also for infusion apparatus. It is equally advantageous for inhalation apparatus, for feeding the product to be for example vaporized by a vaporizing means of the inhalation apparatus.
An administering apparatus such as an injection apparatus or an infusion apparatus generally comprises a reservoir part for storing the product to be administered and a drive device for a single product administration or a dosing and drive device for selection and administration of the product dosage. The reservoir part contains a product reservoir, from which the product or a portion of the product is dispensed through a reservoir outlet by advancing a piston. The drive device advances the piston.
As stated above, a drive device comprising a dosing and drive device may be provided in an administering apparatus for repeated dispensation of product. The dosing and drive device typically comprises a dosing device or a portion of a dosing device and may include an indicator for optically and/or acoustically indicating the selected product dosage.
Assembly of the reservoir part with the drive device, or dosing and drive device, can be problematic as the piston in the reservoir of the reservoir part must be coupled to the drive device and possibly a dosing device or a portion of a dosing device. One problem that can arise is associated with inadvertent reuse of a used reservoir. If a used reservoir is inadvertently assembled with the reusable dosing and drive device, there is the possibility of an incorrect initial setting. An incorrect initial setting may result in an incorrect dosage being administered when the product is first administered after the apparatus has been assembled. This is particularly possible if the administering device is used for self-administration of a fluid, for example, in self-administration of insulin in diabetes therapy.